The invention relates to a magnetic tape apparatus having at least two push buttons which, when their push-button bars are pressed in separately, exert individual functions on apparatus parts. In such apparatus each of the push-button bars is loaded in tension by means of springs in the direction of their initial neutral positions, and is arrested in the pressed-in position. A spring-loaded blocking member can be moved by all push-button bars, and interacts with latches on the push-button bars to be adjusted in such a way that, when a push-button bar is pressed-in, any push-button bar which was arrested beforehand is released for return to the initial position. The individual latches of at least two push-button bars with blocking member parts allocated to the individual latches have latching arrangements of different design.
A magnetic tape apparatus of this type is .[.knwon.]. .Iadd.known from German Patent Specification No. 2,233,127 to which U.S. Pat. No. 3,900,173 corresponds. In this apparatus, several push-button bars are provided with latches which engage into recesses of a transversely displaceable slide. The latches, after they have displaced the slide by means of inclined edges on the recesses during the push-in movement, can drop into allocated latching hollows. The push-button bars thus arrested in the pushed-in position can therefore set certain operating functions in the apparatus. When a second push-button bar is pushed in from its neutral position, this push-button bar also pushes the slide aside via its latch. If the first push-button bar, which had been arrested beforehand, is not secured manually in the pushed-in position, the first push-button bar springs out when the second push-button bar is pushed in.
If both push-button bars are pushed in together for another preset function, the latches of both push button bars drop behind the latching edges of the recesses and thus both are locked. It is only possible to unlock these two push-button bars with the aid of a third push-button bar having an inclined edge which displaces the slide to the extent that both arresting latches are freed from the blocking edges. All push-button bars are preloaded in the outward direction by means of springs, so that they always return to their initial position when the latches are released.
With its latch and the associated slide recess, each individual push-button bar forms a separate latching arrangement. Moreover, the two individually lockable push-button bars have latching arrangements of the same design. In the '173 U.S. Patent there is also a further push-button bar with another latching arrangement which is of such a design that it can disengage the latching arrangements of the two first mentioned push-button bars in the same way as the non-locking release push-button bar.